I agree with WildCoyote. The best/easiest way is to simply count calories. Find out your total daily energy expenditure (TDEE). If you eat 500 calories less than your TDEE, you should lose about a pound a week. If you have a kitchen scale, even better!

I think the best exercise is the one you are motivated to do consistently. A little bit of work done consistently is better than a grand effort that you rarely do.